Published at 11:14 AM PDT on Aug 15, 2017

Receive the latest national-international updates in your inbox

Police officers patrol a pizza restaurant in Sept-Sorts, east of Paris, on August 15, 2017, a day after a girl was killed when a purportedly suicidal driver plowed into the store.

A security guard who deliberately rammed his car into a crowded pizzeria in France told investigators he was a suicidal habitual drug user and had consumed "a large quantity" of painkillers the day before the act that killed an adolescent girl, a prosecutor said Tuesday.

Eric de Valroger, a prosecutor in the town of Meaux east of Paris, described the suspect as "incoherent" and said his interrogation was proving "very complicated" and confusing.

The prosecutor reiterated that he had "totally" ruled out terrorism as a motive for the driver's as-yet unexplained actions Monday night.

De Valroger said it remains unclear if the 32-year-old man intended to kill when he rammed his BMW into the restaurant that had about 30 people inside and on a terrace outside.

"He describes himself as being out of control at the time of the incident. He is very confused about the motives. He says that if he commits an act that sends him to prison, he will be safe," the prosecutor said.

The driver was quickly arrested in what was the latest of several attacks in France and elsewhere using a vehicle as a weapon. De Valroger says the investigation promises to be long.

The prosecutor said the man had a 2010 conviction for drunken driving and told investigators he had abused drugs since he was 9 years old.

He tried reversing out, but several restaurant patrons blocked his path and tried to pull him from the BMW before police arrived, the prosecutor said.

Of the five people most seriously injured, a 44-year-old woman remains in danger, the prosecutor said. The others, including a 3-year-old boy who was flown by helicopter to a Paris children's hospital, are out of immediate danger, he added.